The regulating valve is divided into two kinds, which are straight through single seat and straight through double seat. The latter has the characteristics of large circulation capacity, unbalance operation and stable operation, so it is usually especially suitable for large flow, high pressure drop and less leakage. The regulating valve is mainly used in the water system such as central heating (cold), the flow of pipe network is distributed according to demand, the hydraulic imbalance of the water system is eliminated, the problem of cold and cold ununiformity can be solved, and the energy saving and electricity saving can be saved 15%-20%. Valves of this type should be installed horizontally in pipes. The regulating valve is usually composed of two parts: an electric actuator or a pneumatic actuator and a valve body.

The application of the lower pneumatic control valve in the pipe network is mainly introduced.

The pneumatic regulating valve can set the flow directly according to the design. The valve can automatically eliminate the flow deviation caused by the residual pressure head and pressure fluctuation of the pipeline under the action of water. No matter how the system pressure changes, the valve can keep the set flow constant. The work has become a simple flow distribution, effectively solving the hydraulic imbalance of the pipe network. When the valve is fully open, when the pressure difference between the front and rear valves is 1 kg / cm 2, the medium weight is 1 g / cm 3, the mass of the valve passing through the valve per hour is 3 M / h. For the incompressible fluid, when the Reynolds number is large enough, the water Re>10 5 and the air Re>5.5 * 104 are sufficiently turbulent.